Hallo delwar,
download a new image, format a memory stick, put the image file "VUPLUS" complete with all its files on the memory stick.
turn off the VU duo swith off the switch on the back of the VU put the memory stick in the front USB connection, switch on the VU from the switch at the back and watch the information on the front pannel and when asked push the O.K. button on the VU and wait about 1/2 uur, if you do not have a O.K. button on the VU then just wait and see if the memory stich is being read by the flashing light on the stick.
Hope that this is helpful, i have a clone mini VU+duo and this works for me.
Sucess
cockney_pride
